The Liver

• The largest single organ in the human body.

• In an adult, it weighs about three pounds and is roughly the size of a football.

• Located in the upper right-hand part of the abdomen, behind the lower ribs.

Functions• The liver has more than

200 functions, including:

– Storage of Nutrients– Bile Secretion– Synthesis of plasma

Proteins– Synthesis of cholesterol

Liver Physiology, Larry Frolich, Yavapai College, March 10, 2006

Locate your liver

1. ANATOMY

How Do I work?

Eat.

Your liver creates bile.

Food is digested in the Intestine.

Everything from intestine goes to liver to be used by the body.

Liver Physiology, Larry Frolich, Yavapai College, March 10, 2006

What is bile?• Bile composed of water, ions, bile

acids, organic molecules (including cholesterol, phospholipids, bilirubin)

• Gallstones are mostly cholesterol• Acids and salts emulsify fats for

absorption across wall of small intestines into lacteal lymph capillaries (review)

• Contains waste products from RBC breakdown and other metabolic processing (color of feces from bilirubin in bile)(review)

• Ions buffer chyme from stomach (review)

Liver Physiology, Larry Frolich, Yavapai College, March 10, 2006

Cholesterol—one example of liver processing

• Our body needs cholesterol for– Cell membranes– Vitamin D– Hormones—progesterone and testosterone– Myelin (neuron axonal “wrapping”)– Component of bile salts

• 85% of cholesterol in our blood is “endogenous” or manufactured by our own cells (mostly liver)

• 15% comes from the food we eat• So, is zero-cholesterol good…or even healthy?

Liver Physiology, Larry Frolich, Yavapai College, March 10, 2006

Cholesterol—one example of liver processing

• Our body needs cholesterol for– Cell membranes– Vitamin D– Hormones—progesterone and testosterone– Myelin (neuron axonal “wrapping”)– Component of bile salts

• 85% of cholesterol in our blood is “endogenous” or manufactured by our own cells (mostly liver)

• 15% comes from the food we eat• So, is zero-cholesterol good…or even healthy?